Rice (the seed of the monocot plants Oryza sativa or Oryza glaberrima) is the most important staple food for over two-thirds the world's population, providing a significant proportion of the calories consumed. Inducing greater rates of rice growth can help ensure a greater availability of essential raw materials to the world's growing population.
Rice blast (Magnaporthe oryzae) is a plant-pathogenic fungus that causes a serious disease affecting rice and related plants. It causes economically significant crop losses annually, contributing to an estimated 40% loss in crop yield. Rice blast destroys enough rice to feed millions of people throughout the world every growth season. Since rice is an important food staple for much of the world, the effects of rice blast have a broad impact on human health and the environment. Rice shortfalls contribute directly to human starvation. The rice blast further contributes to crop loss and requires the use of additional resources to compensate for reduced yield caused by disease. There continues to be a great need for methods that reduce rice blast, as well as methods that increase growth in rice plants.
Contamination of rice and other crops with arsenic affects multiple regions, of the world including Bangladesh, China, Chile, India, Mexico, Europe and the United States. Inorganic arsenic is a proven toxin and demonstrated carcinogen. In particular, rice produced in the Bengal Delta Plain of Bangladesh, especially in the arsenic hotspots, accumulates inorganic arsenic, and its consumption contributes to large-scale mass poisoning of the region's peoples. Severe arsenic intoxication is common in Bangladesh and results in skin lesions and neurological injury. Chronic low-level exposure increases incidence of multiple cancers and causes disfigurement and recurring diarrhea. Making this situation worse, elevated arsenic concentrations in soil are phytotoxic and can contribute to decreased grain fill, lowered yield and reduced food availability.
Fortunately, plants have evolved multiple mechanisms to overcome the abiotic stresses encountered during growth, and these inherent survival strategies can be utilized to reduce arsenic assimilation. Currently, rice varieties with reduced arsenic accumulation are in cultivation. In addition, engineering approaches are being utilized to reduce arsenic availability within the soil. Despite these important and substantial efforts, an estimated 50 million people in this region are currently at risk of debilitating arsenic poisoning. There continues to be a great need for sustainable agronomic practices that reduce arsenic concentrations in rice grain.